Activists say heavy battles underway in Yarmouk refugee camp, which is forcing many Palestinians to flee; most Palestinians back rebels, but some have been fighting on regime's side.

Clashes between Syrian rebels and an armed Palestinian group loyal to President Bashar Assad raged inside a Damascus refugee camp Tuesday as opposition fighters pushed deeper into the capital, activists said.

The rebels fighting to topple Assad's regime have made significant tactical advances in the past weeks, capturing air bases and military installations in and around Damascus.

Their offensive in the Palestinian refugee camp of Yarmouk in southern Damascus, which began Friday, is aimed at driving the pro-government Palestinian gunmen out of the camp, which would be another blow to Assad and his loyalists.

When the revolt against Assad's rule began in March 2011, the half-million-strong Palestinian community in Syria tried to stay on the sidelines of the conflict.

But as the civil war deepened, most Palestinians backed the rebels, though some groups - such as the Popular Front for the Liberation of Palestine-General Command - have been fighting on the government side.

The Britain-based Syrian Observatory for Human Rights said the violence in Yarmouk is forcing an exodus of Palestinian refugees and Syrians who came to the camp in past weeks to escape violence elsewhere in the city. The Observatory relies on reports from activists on the ground.

Camp residents said several mortar round landed inside Yarmouk on Tuesday and gunfire has echoed around the area. The residents spoke on condition of anonymity, fearing for their safety.

They said there were no Syrian government troops in the camp and that most of the fighting was between rebels and gunmen from the PFLP-GC. The group is led by Ahmed Jibril, Assad's longtime ally.

Syrian pro-government Al Watan newspaper said Tuesday the army could be preparing an operation "to cleanse the Yarmouk camp of gunmen."

On Monday, Syrian Foreign Minister Walid al-Moallem claimed the clashes at the camp were triggered by the al-Qaida-linked Jabhat al-Nusra group, which was designated by the Obama administration a terrorist organization last week.

Al-Moallem warned Palestinians inside the camp not to harbor terrorist fighters.
There were no immediate reports of casualties from Tuesday's fighting. At least eight people were killed in the airstrike on Yarmouk on Sunday, according to Syrian activists.

U.S. State Department spokesperson Victoria Nuland said Monday the United States is "deeply concerned" by reports that dozens of civilians were killed or wounded in Yarmouk as a result of aerial bombardment and fighting.